#include <iostream>
#include<vector>
#include <string>
#include <algorithm>
#include <cstring>
#include <cstdlib>
using namespace std;

unsigned long long factorial(unsigned long long num) {
    return num <= 1 ? 1 : num * factorial(num - 1);
}

string multi(string a, string b) {
    vector<int> ret(a.size() + b.size());
    reverse(a.begin(), a.end());
    reverse(b.begin(), b.end());
    for (int i = 0; i < a.size(); ++i) {
        for (int j = 0; j < b.size(); ++j) {
            ret[i + j] += (a[i] - '0') * (b[j] - '0');
        }
    }
    string retstr;
    int carry = 0;
    for (int i = 0; i < ret.size(); ++i) {
        int dig = (ret[i] + carry) % 10;
        //if (dig) {
            retstr += to_string(dig);
        //}
        carry = (ret[i] + carry) / 10;
    }
    while (carry) {
        retstr += to_string(carry % 10);
        carry /= 10;
    }
    int j = retstr.size() - 1;
    while (j >= 0) {
        if (retstr[j] == '0') {
            retstr.pop_back();
            j--;
        }
        else {
            break;
        }
    }
    reverse(retstr.begin(), retstr.end());
    return retstr;
}

int main()
{
     //for(int i = 1; i < n; ++i){
     //  //string tmp = i * (i - 1) / 2;
     //    string tmp;
     //    if (i % 2) {
     //        tmp = multi(to_string(i), to_string((i - 1) / 2));
     //    }
     //    else {
     //        tmp = multi(to_string(i / 2), to_string(i - 1));
     //    }
     //    //cout << i << ":" << tmp << endl;

     //    if (tmp.size() > 2 && tmp[tmp.size() - 1] == '0' && tmp[tmp.size() - 2] == '0') {
     //      cout << i << ":" << tmp << endl;
     //  }
    long long n = 1000;


    vector<string> dp(n + 1);
     string tmp("1");
    for (int i = 2; i < n; ++i) {
        //dp[i + 1] = dp[i] * (i + 1);
        tmp = multi(tmp, to_string(i));
        if (i % 5 == 0) {
            int j = tmp.size() - 1;
            while (tmp[j--] == '0') {

            }
            
            cout << i << ":" << (tmp.size() - j - 2) << endl;
        }
    }

    //cout << multi(string("2"), string("500000"));


    return 0;
}


//
        // 121
        // 231
        // 121
//        363
//       242
// 
//
